Nodes may need to be discharged in various circumstances, such as when a device or circuit is shut down or changes state.
It is known to discharge a node by coupling a resistance across the node's terminals. However, if the capacitance at the discharge node is too large, peak current can be too high. Furthermore, a node generally needs to be discharged before expiry of a particular time period, so compliance with these time specifications limits a resistor's size and therefore the size of capacitance that can be discharged.
A node may also be discharged using a current mirror sink, which involves using an input current to control current at the node being discharged. The current mirror approach is more controlled and has a linear slew at the discharge node. However it requires a very large silicon area.
Therefore, there is a need to provide an improved discharge circuit that can cope with relatively large node capacity, while also maintaining an element of control.